03 Toppling (Kuzushi)

Toppling is the action that leads to unbalancing. In this state the base of support is reduced to a line and the mass is littering on a precipace. An object is easier to topple when

1. It has a higher centre of mass

2. The base of support in the direction of the topple is narrow

3. The mass is lighter.

Points 1 & 2 can be manipulated but 3 is harder to change.

A toppled object can generate not horizontal force and so becomes light to move an manipulate.

Thus

1. Achieving kuzushi in uke at the instant of contact mean the technique is already over and the battle already one. The rest is the busy work of technique that imparts the finishing skills of the art

2. As uke if you can achieve kuzushi in nage you can defeat their techniques without effort.

Again this is the immovable body, laugh at the techniques of others that are much lauded by masters and rarely explained.

Some of the above are explored in the application section but I digress, the figure below shows the toppling action on a body. insert an uke in front of side view to imagine your choice of technique, or a reduced subset like aikiage

Toppling action

The optimum angle is at 90 degrees to the topping line. At this angle no energy is wasted pushing into the ground or expended into trying to lift uke up. instead there is a nice class 2 lever, arguably the most efficient for heavy lifting.